nfsvers=3
> NAME PROPERTY VALUE SOURCE
> mainpool/storage sync standard default
sync=standard
This is expected behaviour for this combination. NFS 3 semantics are
for persistent writes at the server regardless - and mostly also
for NFS 4.
The async client mount option relates to when the writes get shipped
to the server (immediately or delayed in dirty pages), rather than to
how the server should handle those writes once they arrive.
You could set sync=disabled if you're happy with the consequences, or
even just as a temporary test to confirm the impact. It sounds like
you would be since that's what you're trying to achieve.
There is a difference: async on the client means data is lost on a
client reboot, async on the server means data may be lost on a server
reboot (and the client/application confused by inconsistencies as a
result).
Separate datasets (and mounts) for data with different persistence
requirements can help.
--
Dan.